The number of distinct Android malware specimens detected will reach 1 million this year, predicts Trend Micro in its annual security roundup report, noting that the surge in Android malware has grown at a faster clip in three years than was seen in PC-based malware in its first 14 years.

"Last year we predicted the amount of Android malware to be at 125,000 and it actually ended up at 350,000," says Raimund Genes, CTO at Trend Micro, discussing the "Evolved Threats in a 'Post-PC' World" report that Trend released today. "Now we're predicting an additional 650,000 new pieces this year."

Considering it all in an historic context, Genes notes that the first Microsoft-based PC viruses were mainly "just to make fun of Microsoft," as a prank, joke or protest. The growth in the vicious form of cybercrime exploiting PCs for economic gain came much later. But Android malware from the beginning has been brazenly exploitative, such as sending spammy SMS messages to smartphones that incur costs to victims.

The Trend Micro report out today contains information based on threat data aggregated by Trend through analysis aggregated through its cloud-based sensors and customer network activity, among other sources. With much malware originating from websites these days, Trend says its analysis shows the top regional source of malicious URLs is the U.S. at 23%. But 56% of malicious URLs have to be classified as "unknown" in terms of country. That's because the attackers setting up these malicious URLs are getting better at hiding their traces, Gene sayss.

Trend Micro also kept a running tab in 2012 of the social-engineering keywords used by attackers to reel in victims of their malware one way or another during 2012. In the early part of 2012, the phrases "law enforcement," "tax season," "London 2012 Olympics" and "Tibet," were most used to try and trick someone into downloading malware or opening malware-laden attachments, while in the second half of last year "iPhone 5," "World of Warcraft," "Christmas," and "Thanksgiving" were the top keyword lures.